Rolling bearings comprise a plurality of rolling bodies that roll on raceways during operation. To reduce the friction during rolling, it is typical to provide the rolling bearing with a lubricant. However, during operation, the quality of the lubricant can degrade due to long-term loading, aging, or thermal effects, or the lubricant can be lost due to cracks, etc. A consequence of degraded lubricant or reduced quantity of lubricant is that the friction in the rolling bearing increases and therefore, among other things, the service life of the rolling bearing is shortened.
In publication WO 2009/030202 A1, a measurement device and a method for analyzing the lubricant of a rolling bearing is presented. The measurement device comprises a plurality of transmitter diodes that transmit light in the near-infrared range onto a measurement location behind a measurement window that is in contact with the lubricant. The measurement device further comprises a receiving device that receives the reflected light of the transmitter diodes. Because certain wavelength ranges are significant for the quality states of the lubricant, by evaluating a spectrum of the light reflected from the measurement location, a conclusion can be made on the quality and/or quantity of lubricant in the rolling bearing.
The publication DE 10 2010 015 084 A1 that forms the closest prior art relates to a sensor part for an infrared sensor and to a method for its production. The sensor part is used, e.g., for use in the measurement device of the above publication. The sensor part comprises a contoured printed circuit board, wherein the sensor diodes are constructed as so-called DIEs. The sensor part is held in a sleeve that is filled with a gel of a silicon basis that is transparent to IR radiation and thus to the measurement radiation, so that, first, the opposing position of the transmitter diodes and the receiving device no longer changes, second, oxygen and water vapor are displaced, and third, the optical transition between the transmitter diodes built as DIEs to the environment is improved.